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RADT 355- Unit 1
Radiobiology review of chapters 1-3 major concepts
Question | Answer |
---|---|
Degree to which the diagnostic study accurately reveals the presence or absence of a disease in the patient | Diagnostic Efficacy |
What is another term that means the same as the ALARA principle? | ORP= Optimization for radiation protection. Keeping the radiation exposure and consequent dose as low as reasonably achievable |
How can a radiographer improve understanding and reduce fear/anxiety for the patient? | Use BERT. Background equivalent radiation time. |
BERT compares the amount of radiation received with _______. | a natural background radiation received over a specific period of time. Days, weeks, months, etc. |
Amount of energy transferred by ionizing radiation | Radiation dose |
_______ has both a beneficial and a destructive potential. | Ionizing radiation |
T or F. Ionizing radiation produces electrically charged particles that can cause biologic damage on molecular, cellular, and organic levels in humans. | True |
The two types of radiation dose are? | Equivalent dose and effective dose |
Information obtained from the exam benefit patient care, increase lifespan, have no affect, or decrease lifespan | Risk- Benefit Continuum |
Equivalent dose (EqD) is measured in, Effective dose (EfD) is measured in, | EqD measured in Sievert (Sv), EfD measured in REM |
What three radiation disasters did we gain understanding from? | Three mile island, Chernobyl, Japan |
For the average population, what is the total annual background radiation? | 6.25 millisievert |
What scale ranks the severity of radiation incidents? | International Nuclear and Radiological Event Scale (INES) |
A radiation quantity used for radiation protection purposes when a person receives exposure from various types of ionizing radiation | Equivalent dose (EqD) |
Takes into account the dose for all types of ionizing radiation to irradiated organs or tissues in the body. | Effective dose (EfD) |
A patient receives a chest x-ray. Using BERT, how many days of natural background radiation is the single chest x-ray equivalent to? | 10 days |
A patient has a UGI exam done. Using BERT, how many years of natural background radiation is the single UGI exam equivalent to? | 1.5 years |
What are three characteristics of the electromagnetic spectrum? | Wavelength, energy and frequency |
X-rays possess high energy, high frequency and ____ wavelength | Short |
What are the four types of radiation? | Primary, scatter, leakage, remnant (exit) radiation |
Direct and indirect transmission of x-ray photons | Attenuation |
How can a radiogapher limit indirect transmission of photons? | Grids and air-gap technique |
T or F. Some absorption must occur to form a diagnostic x-ray image. | True |
What is the best way to reduce scatter radiation? | The use of collimators |
Produces an Auger electron as a secondary process from photoelectric absorption. An inner electron is removed from an atom in a photoelectric interaction, causing an inner shell vacancy, causing an emission of an auger electron. | Auger effect |
Occurs at energies above 10 mEv | Photo disintegration |
Interactions with matter that are not in diagnostic energy range | Pair production and photo disintegration |
Bending of photon path. Degrades appearance of a completed radiographic image by blurring the sharp outlines of dense structures. | Small-angle scatter |
Also known as classic, elastic, unmodified scattering. Interacts with entire atom and is never ionized. | Coherent scattering |
Net effect of coherent scattering. The process of which the photon energy is absorbed and then reradiated in a different direction with no change in wavelength. | Rayleigh scattering |
Another kind of coherent scattering. Occurs when a low-energy photon interacts with one or more free electrons. | Thompson scattering |
What happens to patient dose when kVp increases? | Patient dose decreases |
Type of energy an x-ray photon possesses? | Kinetic |
This type of effect is called a radiationless effect. It is more prevalent in materials with a higher atomic number. It does not produce radiation therefore it has no effect on patient dose. | Auger effect |
Of the four types of radiation, which is most useful? | Primary Beam |
Photons with middle energy are more likely to interact with? | Orbital electrons |
Photons with the lowest amount of energy are more likely to interact with? | Whole atom |
The less a given structure attenuates the _____ its radiographic density will be. | Greater |
What factors influence attenuation? | Mass density, thickness of body part, atomic number, and energy range |
An increase in photoelectric absorption will predominately occur with | Increased atomic number, decreased energy of x-ray photon, increased mass density, thicker structures |
If two structures have the same density and atomic number but one is twice as thick as the other, which structure absorbs twice as many photons? | Thicker structure |
What is the function of filtration in diagnostic x-ray beam? | Hardens the beam by removing low energy photons. Decreases patient dose. |
What year was the first radiation fatality? Who was it? | Clarence Daly in 1904 |
Received quantity of radiation that causes diffuse redness over an area of skin. Varied for each person-not precise | Skin Erythema Dose |
A dose that occupational workers could be exposed to without having any harmful acute affect | Tolerance Dose |
A dose that is below which an individual has a chance to sustain specific biological damage | Threshold Dose |
T or F. Neither tolerance dose nor threshold dose are currently being used for the purposes of radiation safety | True |
Acute or early effects. Appear within minutes, hours, days or weeks. | Short-term somatic effects |
What are some long-term somatic effects? | Cancer, embryologic effects, formation of cataracts |
Biologic effects of ionizing radiation on generations yet unborn | Genetic effects (Heritable Effects) |
What are some acute somatic effects? | Nausea, fatigue, diffuse redness of skin, fever, loss of hair, intestinal disorders, shedding of the outer layer of skin |
The unit that measures radiation intensity | Roentgen (R) or Gray (Gy) |
Radiation absorbed dose. Responsible for patient dose. | RAD or Gray(Gy) |
Radiation equivalent man. Responsible for occupational dose. | REM or Sievert(Sy) |
The unit of quantity of radioactive materials | Curie (Ci) or Bequerel (Bq) |
This quantity, describes radiation exposure of a population or group from low doses of different sources of ionizing radiation. | Collective effective dose (ColEfD) |
What two systems can radiation units be expressed in? | International System (SI) or the traditional system |
How is the conversion of the roentgen to coulombs per kilogram accomplished? | Multiplying the number of roentgens by 2.58 x (10) to the negative fourth power |
Amount of energy transferred on average by radiation to an object | Linear energy transfer (LET) |
The higher the LET the more biological damage and the higher ______ factor. | Quality |
What is the unit of collective effective dose? | Person-sievert |
The weighting factor that takes into account the relative risk associated with irradiation of different body tissues | Tissue weighting factor |
If absorbed dose is stated in rad, how can gray can be determined? | Dividing by 100 |
In the International System, what is the exposure unit measured in? | Coulombs per kilogram (C/kg) |
How do you convert GRAY to RADS? | Multiply number of Grays by 100 |